1. Field of the Invention
The present invention relates generally to enhancing building security and particularly to facilitating the removal of operating knobs from manually operated door lock inside actuators to thereby prevent the use of such an actuator to unlock an access door to a secured area. More specifically, this invention is directed to locking devices for doors, such locking devices having a manually operable inside actuator, and especially to door locks where the control knob or lever of the inside actuator may be easily removed and reinstalled. Accordingly, the general objects of this invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for incorporation into locks which are intended to be installed on building entry doors having one or more glass panels therein. Such locks are commonly installed in proximity to a thumb operated latch mechanism and may take the form of a dead bolt lock. These entry-way locks are characterized by inside and outside actuators which, via an adaptor or tailpiece, operate a bolt. The outside actuator will be key operated while the inside actuator will be a manually operable control member such as a turnknob.
In order to ensure the ability to rapidly evacuate the premises secured by the lock in the case of an emergency, the inside actuator will not be key operated. Thus, the bolt may be withdrawn and the door opened from the inside merely by grasping and rotating the turnknob of the inside actuator. This arrangement, however, presents one desiring to gain unauthorized entry with the possibility of breaking a glass panel in the door in order to reach and subsequently operate the turnknob of the inside actuator.
There has been a long-standing desire to provide some mechanism for disabling the inside actuator of a lock when the premises secured by that lock are to be left vacant. This desire, for economic and/or aesthetic reasons, is not fulfilled by employment of a supplemental locking device on the door. This desire, if to be successfully addressed, must achieve the function of disabling the inside actuator through a procedure which is highly reliable and extremely easy to implement.